21002121201210 has 128 divisors (see below), whose sum is σ = 51906845675520. Its totient is φ = 5434530506496.

The previous prime is 21002121201203. The next prime is 21002121201221. The reversal of 21002121201210 is 1210212120012.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21002121201210.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1319303631 + ... + 1319319549.

It is an arithmetic number, because the mean of its divisors is an integer number (405522231840).

Almost surely, 2^{21002121201210} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21002121201210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25953422837760).

21002121201210 is an abundant number, since it is smaller than the sum of its proper divisors (30904724474310).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21002121201210 is a wasteful number, since it uses less digits than its factorization.

21002121201210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19092.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21002121201210 its reverse (1210212120012), we get a palindrome (22212333321222).

The spelling of 21002121201210 in words is "twenty-one trillion, two billion, one hundred twenty-one million, two hundred one thousand, two hundred ten".